A gas turbine system includes in the simplest case, a compressor, a combustion chamber as well as a turbine. In the compressor, a compression of sucked-in air takes place, to which a fuel is subsequently added. In the combustion chamber, combustion of the mixture is undertaken, with the combustion gases being fed to the turbine, by which energy is drawn from the combustion gases and converted into mechanical energy.
These days, gas turbine systems are equipped with multi-stage combustion chambers, consisting of a plurality of burner stages to be operated in parallel, which depending on the utilization of the gas turbine systems, can be operated either individually or jointly. Typically, the parallel burner stages can comprise a main burner stage and a pilot burner stage, in which case the flame of the pilot burner stage should more particularly stabilize the flame of the main burner stage.
During the stationary operation of a gas turbine system, the released quantity of heat should, in essence, be kept constant. However, variations in the fuel quality lead to variations in the released quantity of heat and thereby in the efficiency of the system. That is why, in order to compensate for variations in the fuel composition, gas turbine systems have a control device, by means of which the efficiency or the exhaust gas temperature is likewise kept constant in relation to the quantity of heat released.
In general, the efficiency or the exhaust gas temperature is kept constant by adjusting the supply of fuel to the main burner stage by means of a regulator, which determines the fuel quantity.
However, this procedure can cause increased emissions or combustion fluctuations.